Interference Management in Heterogeneous Networks with Blind Transmitters

Future multi-tier communication networks will require enhanced network capacity and reduced
overhead. In the absence of Channel State Information (CSI) at the transmitters, Blind Interference
Alignment (BIA) and Topological Interference Management (TIM) can achieve optimal Degrees
of Freedom (DoF), minimizing network’s overhead. In addition, Non-Orthogonal Multiple Access
(NOMA) can increase the sum rate of the network, compared to orthogonal radio access techniques
currently adopted by 4G networks. Our contribution is two interference management schemes, BIA
and a hybrid TIM-NOMA scheme, employed in heterogeneous networks by applying user-pairing and
Kornecker Product representation. BIA manages inter- and intra-cell interference by antenna selection
and appropriate message scheduling. The hybrid scheme manages intra-cell interference based on NOMA
and inter-cell interference based on TIM. We show that both schemes achieve at least double the rate of
TDMA. The hybrid scheme always outperforms TDMA and BIA in terms of Degrees of Freedom (DoF).
Comparing the two proposed schemes, BIA achieves more DoF than TDMA under certain restrictions,
and provides better Bit-Error-Rate (BER) and sum rate perfomance to macrocell users, whereas the
hybrid scheme improves the performance of femtocell users.